Thin film transistor liquid crystal displays (TFT-LCDs) belong to a major kind of display devices. With the development of technology, consumers have higher requirements on the display effect of electronic products. In order to improve the display effect of a display device, enhance the display performance of a thin film transistor, and reduce power consumption, a resin planarization layer is usually formed on the thin film transistor.
But generally when a pattern of a planarization layer and a pattern of a passivation layer are formed, it is necessary for them to be formed through two patterning processes. Because a thickness of the planarization layer is relatively large compared with a thickness of the passivation layer, as illustrated in FIG. 1, the aperture of a via hole in the planarization layer is relatively large. Whether a half-overlay or a full-overlay manner is adopted for the via holes 11 in the passivation layer and the planarization layer, two via holes 11 in the planarization layer and the passivation layer will be made to be too large. Thus, the via holes 11 in the planarization layer and the passivation layer cannot be overlapped completely, which greatly reduces the aperture ratio of the display device. Thereby, the display effect of images is affected.